Bundee Aki was sent off as Connacht were beaten by defending United Rugby Championship winners the Stormers in Stellenbosch.
Ireland international Aki was penalised for a dangerous clear-out midway through the second half, extinguishing any hope of a fightback from the Irish province.
Evan Roos touched down early for the hosts and, though they could not add another try before the break, they took a 13-8 lead into half-time thanks to the kicking of Manie Libbok, with Dylan Tierney-Martin going over for the visitors.
The RTÉ Rugby panel discuss Bundee Aki's dismissal against the Stormers and his "confrontational" behaviour towards the match officials
Connacht were 19-8 down when Aki was given his marching orders and quickfire tries from Andre-Hugo Venter and Hacjivah Dayimani put the result beyond doubt, with Jack Aungier crossing for a late consolation.
Marcel Theunissen wrapped up the bonus point after the hooter.
Roos dominated the end-of-season awards last term and took only three minutes to make an impact this time around.
Evan Roos' superb early try has the Stormers ahead against Connacht #URC
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The No 8 exploited a gap in the Connacht defence and made light work of Mack Hansen's attempted tackle as his rampaging run sent him over in the corner.
Libbok slotted the conversion and added a penalty after Conor Fitzgerald had got Connacht off the mark from the tee.
The Stormers No 10 was off-target with a relatively straightforward penalty after 22 minutes but normal service was resumed when he made it 13-3 five minutes later.
Marvin Orie was then sin-binned for an accumulation of Stormers offences and Connacht quickly made their hosts pay.
Half-time: Stormers 13-8 Connacht
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Tierney-Martin drives over just before the break as the Irish province take advantage of their extra man
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Following a period of sustained pressure on the Stormers five-metre line, Connacht eventually drove Tierney-Martin over, although Fitzgerald was wayward with the conversion.
Libbok scored two more penalties either side of Connacht losing Caolin Blade to a serious-looking ankle injury early in the second half.
The visitors thought they had closed the gap when Tom Farrell went over after collecting a David Hawkshaw cross-kick but the try was chalked off for Aki's dangerous clear-out on Seabelo Senatla in the build-up – an offence that earned Aki the red card.
That dismissal swung momentum decisively in the Stormers’ favour and Venter touched down at the end of a mesmerising passage of play to make it 26-8 with the help of Libbok’s conversion.
Dayimani quickly added another and although Aungier’s try – converted by Hawkshaw – gave Connacht fans something to smile about, it was Theunissen who had the final say at the death, with Libbok adding the extras.